Nut cold header forming device

Abstract

The application discloses a nut cold header forming equipment and relates to the technical field of cold headers. The equipment comprises a fixed die seat, a movable die seat, a forming die and a top piece. The forming die is detachably installed on the fixed die seat, and the top piece is detachably installed on the movable die seat and oppositely arranged with a die cavity of the forming die. The forming die comprises a seat body, a pushing ring body and a plurality of modules. The seat body is provided with a conical hole, the pushing ring body is rotatably arranged at the bottom of the conical hole, and the plurality of modules are slidably arranged in the conical hole and abut against the pushing ring body. After the pushing ring body is rotated, the modules can be moved downward under the action of gravity to release the extrusion on the material column. The equipment is further provided with a bushing, an intermediate body, an elastic pushing rod and a lubricating structure, can realize stable folding and smooth loosening of the forming die, and can complete automatic demolding in cooperation with the elastic pushing rod. The application can improve the stability of the nut cold heading forming and demolding process, reduce the damage of workpieces and the die, prolong the service life of the die, and is suitable for cold heading processing of various nut blanks.

Description

Technical Field

[0001] This invention relates to the field of cold heading machine technology, specifically to a nut cold heading forming equipment. Background Technology

[0002] Nuts, as fasteners widely used in mechanical connections, are typically mass-produced using cold heading, a process that offers advantages such as high processing efficiency, high material utilization, and good product mechanical properties, making it widely used in the fastener manufacturing industry. The nut cold heading machine, as the main equipment for this process, applies pressure to a metal blank through the cooperation of a fixed mold and a moving mold, causing it to plastically deform within the mold cavity, ultimately forming a nut blank that meets dimensional requirements.

[0003] Among them, the invention patent with publication number CN103909205A, entitled "Cold Forging Device and Cold Forging Process for Pipe Nuts", discloses a cutting mechanism, a feeding mechanism, a conveying mechanism, and six molds. The feeding mechanism is positioned corresponding to the cutting mechanism; the conveying mechanism moves between the feeding mechanism and the molds to feed the material; the molds include a first mold for pre-forging chamfering, a second mold for forming the rod diameter, a third mold for pre-forging the hexagonal shape of the head, a fourth and a fifth mold for reverse extruding the inner hole and simultaneously fine-forging the hexagonal shape of the head, and a sixth mold for through holes. The six molds are arranged in sequence, and the workpiece is directly formed in the molds. The processing process is continuous and the forming speed is fast.

[0004] However, the mold cavity of the forming mold is a closed cavity of fixed size. After cold heading, the workpiece fits tightly against the inner wall of the mold cavity, which can easily lead to workpiece jamming and tearing during demolding. Forced demolding can also cause wear on the inner wall of the mold, reducing its service life. At the same time, the fixed structure of the mold cannot adjust the cavity size according to the forming and demolding requirements, making module disassembly and maintenance inconvenient. It is difficult to balance forming accuracy and demolding smoothness, affecting the processing quality and production stability of the finished nut. Summary of the Invention

[0005] To overcome the above-mentioned defects, embodiments of the present invention provide a nut cold heading forming equipment, which solves the technical problem in the prior art that after cold heading, the workpiece is tightly attached to the inner wall of the mold cavity, and the workpiece is prone to jamming and tearing during demolding.

[0006] According to one aspect, at least one embodiment of the present invention provides a nut cold heading forming apparatus, comprising: A mold base, on which a forming mold is detachably mounted; The molding die includes a base, a push assembly, and several modules. The base has a conical hole. The push assembly is rotatably disposed in the base and located at the bottom of the conical hole. Several modules are slidably disposed in the conical hole and are arranged at intervals along the circumference. A moving mold base, on which a top piece is detachably mounted; When the push assembly rotates and moves upward, several modules can move upward synchronously and retract to form a mold cavity, and then the push member of the moving mold base presses the material column in the mold cavity downward to form a nut. After the jacking assembly rotates and moves downward, several modules can move downward under their own gravity to separate from the nut.

[0007] Optionally, the base has an internally threaded hole located below the tapered hole, the internally threaded hole communicating with the tapered hole, and the forming mold further includes: The bushing has an external thread, which is threaded to the internal threaded hole. The bushing has an axially opened through hole that communicates with the tapered hole. The upper end face of the bushing is used to support the push assembly.

[0008] Optionally, the push assembly includes a push ring and an intermediate body. The bottom of the intermediate body has a first spiral boss, and the top of the push ring has a second spiral boss. When the push ring rotates, the second spiral boss can push the first spiral boss to drive the intermediate body to move upward, thereby simultaneously pressing against several modules to make the modules retract into the mold cavity.

[0009] Optionally, a limiting groove is provided on the inner wall of the tapered hole, and a limiting protrusion is provided on the outer wall of each module, wherein the limiting protrusion slides in conjunction with the limiting groove.

[0010] Optionally, the molding die further includes: An elastic push rod is disposed through the fixed mold base and the forming mold, and can be moved upward to extend into the mold cavity. The elastic push rod is used to push the formed material column out of the mold cavity.

[0011] Optionally, the elastic push rod includes: The rod has one end extending through the push ring and the intermediate body to the mold cavity, and the other end extending through the bushing and out of the fixed mold base; An end cap is provided at the lower end of the rod body. The end cap is connected to a rotating shaft. The rotating shaft can drive the rod body to rotate and move axially to push the material column. The rotating shaft can also drive the rod body to rotate so that the rod body drives the pushing ring body to rotate. The spring has one end abutting against the inner top wall of the bushing and the other end abutting against the end cap.

[0012] Optionally, the push ring is sleeved on the rod, the rod has an axially extending keyway, the push ring has a fixing key, the fixing key is set in the keyway, and the rod can drive the push ring to rotate.

[0013] Optionally, the seat body has an oil cavity, and the outer wall of the seat body is provided with an oil injection hole, which communicates with the oil cavity. The oil cavity is used to contain grease for lubricating the push ring, the intermediate body and the module.

[0014] Optionally, a sealing block is provided inside the oil injection hole.

[0015] Optionally, the top member includes: The mounting base has a threaded hole, and the mounting base is threadedly connected to the moving mold base; A fixing rod is provided on the mounting base and extends downward.

[0016] The beneficial effects of this invention are as follows: This invention employs a combination structure of a base, a rotatable push assembly, and multiple sliding modules in the forming mold. This allows the modules to move downwards under gravity after the push assembly rotates, relieving radial compression on the material column. This enables the mold cavity to maintain dimensional stability during cold heading and actively releases the mold cavity during demolding. This effectively prevents the workpiece from getting stuck or scratched against the inner wall of the mold, while also reducing mold wear and improving the processing stability and finished product qualification rate of the nut cold heading. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of the present invention and these drawings without any creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a nut cold heading forming equipment according to one embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the internal structure of the molding die in the embodiment; Figure 3 for Figure 1 A schematic diagram of the molding die structure in the embodiment; Figure 4 for Figure 2 A schematic diagram of the module structure in the embodiment; Figure 5 for Figure 2The embodiment shows a schematic diagram of the structure of the intermediate body and the pushing ring.

[0019] In the diagram: 1. Fixed mold base; 2. Molding mold; 201. Mold cavity; 21. Seat body; 22. Push ring body; 221. Second spiral boss; 23. Module; 231. Limiting protrusion; 24. Tapered hole; 25. Bushing; 26. Intermediate body; 261. First spiral boss; 27. Elastic push rod; 271. Rod body; 272. End cap; 273. Spring; 3. Moving mold base; 4. Ejector; 41. Mounting seat; 42. Fixing rod; 5. Rotating shaft; 6. Oil injection hole; 61. Oil cavity. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0021] To keep the drawings concise, each drawing only schematically shows the parts relevant to the invention; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0022] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0025] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] like Figures 1-5 As shown, this invention illustrates a nut cold heading forming machine according to an embodiment of the present invention. Nut cold heading is a metal plastic forming process and is the mainstream technology for manufacturing standard nuts. In actual production, forming accuracy, demolding smoothness, and mold life directly determine production efficiency and product qualification rate. Traditional cold heading equipment molds are mostly fixed integrated or fixed split types. During forming, the mold rigidity constrains the dimensions to ensure accuracy, and demolding can only be done by force, which can easily cause problems such as workpiece tearing, mold inner wall scratching, and mold jamming and machine shutdown. To address the above defects, this embodiment provides a nut cold heading forming machine that can be opened and closed, with linked demolding and self-lubrication.

[0027] like Figure 1 As shown, the nut cold heading machine forming equipment of this embodiment includes a fixed mold base 1, a moving mold base 3, a forming mold 2, and an ejector 4. The fixed mold base 1 is fixedly installed on the cold heading machine frame, serving as a fixed support for the forming process. The moving mold base 3 is installed on the slider of the cold heading machine and is driven by a crank-connecting rod mechanism or a hydraulic mechanism to perform reciprocating linear motion along the main shaft of the equipment. The forming mold 2 is detachably installed on the side of the fixed mold base 1 facing the moving mold base 3, and forms a mold cavity 201 for forming the material column. The ejector 4 is detachably installed on the side of the moving mold base 3 facing the fixed mold base 1, and is coaxially aligned with the mold cavity 201. When the moving mold base 3 moves towards the fixed mold base 1, the ejector 4 extends into the mold cavity 201 and squeezes the internal material column, causing the metal material column to undergo plastic deformation under high pressure, ultimately forming a nut blank.

[0028] Furthermore, such as Figure 2As shown, the molding die 2 mainly consists of a base 21, an ejector assembly, and multiple modules 23. The ejector assembly includes an intermediate body 26 and an ejector ring 22. The base 21 is cylindrical in shape, with a tapered hole 24 axially formed inside. The small end of the tapered hole 24 faces the moving mold base 3, and the large end faces the interior of the fixed mold base 1. The ejector ring 22 is rotatably mounted inside the base 21 and is located at the bottom of the tapered hole 24 near the large end, allowing it to rotate freely around the main shaft of the equipment. Multiple modules 23 are evenly spaced along the inner circumferential wall of the tapered hole 24 and are slidably mounted on the inner wall of the tapered hole 24. The bottom end face of the module 23 maintains stable contact with the top surface of the ejector ring 22. The multiple modules 23 together form a cylindrical or polygonal mold cavity 201, used to constrain the radial dimension of the material column. When the push ring 22 rotates at a certain angle, the upward support force on the module 23 changes. The module 23 can slide downward along the tapered hole 24 under its own gravity. The enclosing gap between the modules 23 expands, thereby eliminating the radial extrusion of the material column in the mold cavity 201 and providing sufficient space for demolding.

[0029] To improve the installation stability and smooth rotation of the push ring 22, the base 21 has an internally threaded hole behind the tapered hole 24, which is coaxially connected to the tapered hole 24. The forming mold 2 also has a bushing 25, the outer wall of which is machined with external threads. The bushing 25 is screwed into the internally threaded hole through the external threads to achieve axial positioning and detachable fixation. The bushing 25 has an axially penetrating through hole inside, which is coaxially connected to the tapered hole 24. The end of the bushing 25 facing the tapered hole 24 forms an annular platform. The bottom end face of the push ring 22 slides against the annular platform, which ensures that the push ring 22 can rotate freely and restricts its axial backward movement, ensuring the stability of the module 23 during the forming process.

[0030] To ensure uniform force distribution and reliable retraction of module 23, an intermediate body 26 is provided between module 23 and the push ring 22. The bottom of the intermediate body 26 is machined with a first spiral boss 261, and the top surface of the push ring 22 is machined with a second spiral boss 221. The spiral angles and leads of the two sets of spiral bosses are matched. When the push ring 22 rotates forward, the second spiral boss 221 pushes the first spiral boss 261 upward along the spiral surface, pushing the intermediate body 26 forward axially. Simultaneously, the front face of the intermediate body 26 pushes all modules 23, causing the modules 23 to press upward and tightly retract along the inner wall of the tapered hole 24, ensuring consistent dimensions of the mold cavity 201. When the push ring 22 rotates in the reverse direction, the pushing force of the second spiral boss 221 and the first spiral boss 261 gradually decreases until it disappears, allowing the modules 23 to smoothly move downward under gravity, thus releasing the workpiece.

[0031] To prevent circumferential deflection or misalignment of module 23 during sliding, multiple limiting grooves are formed along the axial direction on the inner wall of the tapered hole 24. Each module 23 has a fixed limiting protrusion 231 on its outer wall, which is embedded in the corresponding limiting groove to form a sliding fit. The limiting grooves constrain the circumferential freedom of module 23 and limit its axial movement stroke, preventing module 23 from coming out of the tapered hole 24. This ensures that module 23 can accurately reset and close after multiple processing cycles, maintaining the dimensional accuracy of the mold cavity 201.

[0032] To achieve automatic demolding of the workpiece after molding, an elastic push rod 27 is provided inside the molding die 2. The elastic push rod 27 passes through the fixed mold base 1 and the molding die 2 in sequence along the axial direction, and its front end can extend into the mold cavity 201 to smoothly push the molded material column out of the mold cavity 201, avoiding manual intervention and improving the degree of automation.

[0033] The elastic push rod 27 is specifically composed of a rod body 271, an end cap 272, and a spring 273. The front end of the rod body 271 passes through the central holes of the push ring 22 and the intermediate body 26 in sequence, extending into the mold cavity 201; the rear end of the rod body 271 passes through the central through hole of the bushing 25 and extends to the rear of the fixed mold base 1. The end cap 272 is fixedly connected to the rear end of the rod body 271 extending out of the fixed mold base 1, and the end cap 272 is connected to the external rotating shaft 5 for transmission. The rotating shaft 5 is driven by a drive motor or transmission mechanism, which can either drive the rod body 271 to move back and forth along the axial direction to complete the push action, or drive the rod body 271 to rotate around the axis, thereby driving the push ring 22 to rotate synchronously, realizing the retraction and release of the module 23. Spring 273 is sleeved on rod 271, with one end abutting against the inner top wall of bushing 25 and the other end abutting against the front end face of end cap 272, providing continuous backward restoring force to rod 271, ensuring that rod 271 can automatically return to the initial position after each ejection, without affecting the next molding.

[0034] To ensure reliable driving of the push ring 22 by the rod 271, the push ring 22 is sleeved on the rod 271. A keyway extending axially is formed on the surface of the rod 271, and a fixing key is fixed to the inner wall of the push ring 22. The fixing key is embedded in the keyway to form a sliding and transmission fit. When the rod 271 rotates, the keyway and the fixing key work together to drive the push ring 22 to rotate synchronously. When the rod 271 moves axially, it can slide relative to the push ring 22 along the keyway. This allows the same rod 271 to simultaneously perform rotational driving and axial pushing functions, simplifying the equipment's transmission structure and improving the synchronization of actions.

[0035] To reduce friction and wear between moving parts and extend the service life of the mold, an oil cavity 61 is provided inside the base 21. An oil injection hole 6 is provided on the outer wall of the base 21, which is directly connected to the oil cavity 61. The oil cavity 61 can be filled with lubricating grease, which flows slowly through a pre-set permeation channel to the mating surfaces of the push ring 22, intermediate body 26, and module 23, continuously providing lubrication and reducing dry friction between metals. A sealing block is provided on the oil injection hole 6, which can be a threaded plug or an elastic plug, to seal the oil injection hole 6, preventing lubricating grease leakage and blocking external metal debris and dust from entering the oil cavity 61, maintaining a clean lubrication environment.

[0036] The top component 4 features a detachable structure for easy and quick replacement of nuts of different specifications. The top component 4 includes a mounting base 41 and a fixing rod 42. The mounting base 41 has a threaded hole at its rear end, which engages with the stud at the front end of the moving mold base 3 via threads, allowing for quick assembly and disassembly and accurate positioning. The fixing rod 42 is fixed to the front end of the mounting base 41 and is coaxially aligned with the mold cavity 201. The front end face of the fixing rod 42 is flat, used to directly extrude the material column, ensuring that the pressure is evenly distributed on the end face of the material column, guaranteeing a flat and uniformly sized end face of the nut blank after molding.

[0037] The complete workflow of this equipment is as follows: Before entering the processing cycle, the rotating shaft 5 drives the rod 271 to rotate 90° in the forward direction. The rod 271 drives the push ring 22 to rotate through the keyway and the fixed key. The second spiral boss 221 pushes the first spiral boss 261 upward, causing the intermediate body 26 to move forward and press all the modules 23 together. The modules 23 enclose to form a dimensionally stable mold cavity 201. After the metal column is fed into the mold cavity 201, the moving mold base 3 moves rapidly towards the fixed mold base 1 under the drive mechanism. The fixed rod 42 of the push member 4 extends into the mold cavity 201 and squeezes the column. The column undergoes plastic deformation under high pressure, filling the mold cavity 201 and completing the cold heading. After the forming is completed, the moving mold base 3 drives the push member 4 to retract and reset. The rotating shaft 5 drives the rod 271 to rotate in the reverse direction. The push ring 22 rotates synchronously in the reverse direction. The spiral push force disappears, and the module 23 slides downward along the tapered hole 24 under its own gravity, releasing the radial compression on the formed workpiece. Subsequently, the rotating shaft 5 pushes the rod 271 forward axially, and the front end of the rod 271 smoothly ejects the molded workpiece from the mold cavity 201, completing the demolding. After demolding, the spring 273 pushes the end cap 272 to drive the rod 271 to return to its original position, and the rotating shaft 5 rotates forward again to retract the module 23, and the equipment enters the next processing cycle.

[0038] It is understood that the drive mechanism, feeding mechanism, positioning mechanism, sealing structure, etc., which are not described in detail in this embodiment, are all implemented using conventional technical means in the field to ensure the integrity of the overall structure of the equipment and its stable and reliable operation.

[0039] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A nut cold heading forming equipment, characterized in that, include: A fixed mold base (1) is provided with a molding die (2) which can be detachably mounted on the fixed mold base (1); The molding die (2) includes a base (21), a push assembly and several modules (23). The base (21) has a conical hole (24). The push assembly is rotatably disposed in the base (21) and located at the bottom of the conical hole (24). Several modules (23) are slidably disposed in the conical hole (24) and are arranged at intervals along the circumference. The moving mold base (3) is provided with a top piece (4) that can be detachably installed on the moving mold base (3); When the push assembly rotates and moves upward, several modules (23) can move upward synchronously and retract to form a mold cavity (201), and then the top piece (4) of the moving mold base (3) presses the material column in the mold cavity (201) downward to form a nut. When the push assembly rotates and moves downward, several modules (23) can move downward under their own gravity to separate from the nut.

2. The nut cold heading forming equipment according to claim 1, characterized in that, The base (21) has an internally threaded hole located below the tapered hole (24), the internally threaded hole communicating with the tapered hole (24), and the forming mold (2) further includes: The bushing (25) has an external thread, and the bushing (25) is threaded to the internal threaded hole through the external thread. The bushing (25) has an axially opened through hole inside, and the through hole communicates with the tapered hole (24). The upper end face of the bushing (25) is used to support the push assembly.

3. The nut cold heading forming equipment according to claim 2, characterized in that, The push assembly includes a push ring (22) and an intermediate body (26). The intermediate body (26) has a first spiral boss (261) at the bottom and a second spiral boss (221) at the top. When the push ring (22) rotates, the second spiral boss (221) can push the first spiral boss (261) to drive the intermediate body (26) to move upward, thereby simultaneously pressing against several modules (23) so that the modules (23) are gathered in the mold cavity (201).

4. The nut cold heading forming equipment according to claim 1, characterized in that, The inner wall of the tapered hole (24) is provided with a limiting groove, and the outer wall of each module (23) is provided with a limiting protrusion (231), which slides in cooperation with the limiting groove.

5. The nut cold heading forming equipment according to claim 3, characterized in that, The molding die (2) also includes: An elastic push rod (27) is provided through the fixed mold base (1) and the forming mold (2), and can be moved upward to extend into the mold cavity (201). The elastic push rod (27) is used to push the formed material column out of the mold cavity (201).

6. The nut cold heading forming equipment according to claim 5, characterized in that, The elastic push rod (27) includes: The rod (271) extends from one end through the push ring (22) and the intermediate body (26) to the mold cavity (201), and from the other end through the bushing (25) and out of the fixed mold base (1). An end cap (272) is provided at the lower end of the rod (271). The end cap (272) is connected to a rotating shaft (5). The rotating shaft (5) can drive the rod (271) to rotate and move axially to push the material column. The rotating shaft (5) can also drive the rod (271) to rotate so that the rod (271) drives the pushing ring (22) to rotate. The spring (273) has one end abutting against the inner top wall of the bushing (25) and the other end abutting against the end cap (272).

7. The nut cold heading forming equipment according to claim 6, characterized in that, The push ring (22) is sleeved on the rod (271). The rod (271) has an axially extending keyway. The push ring (22) has a fixing key inside. The fixing key is set in the keyway. The rod (271) can drive the push ring (22) to rotate.

8. The nut cold heading forming equipment according to claim 3, characterized in that, The seat (21) has an oil cavity (61) inside, and an oil injection hole (6) is provided on the outer wall of the seat (21). The oil injection hole (6) is connected to the oil cavity (61), and the oil cavity (61) is used to contain grease for lubricating the push ring (22), the intermediate body (26) and the module (23).

9. The nut cold heading forming equipment according to claim 8, characterized in that, A sealing block is provided inside the oil injection hole (6).

10. A nut cold heading forming equipment according to claim 1, characterized in that, The top component (4) includes: Mounting base (41) has a threaded hole, and the mounting base (41) is threadedly connected to the moving mold base (3); A fixing rod (42) is provided on the mounting base (41) and extends downward.

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